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Read this little gem in the Vray docs (in the notes for a VrayLightMtl), "If you know the photometric power of a self-illuminated object in lumens (e.g. 1700 lm for a 100-watt bulb) you can calculate the multiplier for VRayLightMtl if you divide the lumens by the surface area of the object in meters, provided that the self-illuminated color is pure white."
So let's say we have a mesh of a light bulb. A light bulb is around 8cm in diameter. So the surface area of a 8cm sphere would be about 200cm or 2m (Area= pi times diameter squared). So 1700 lm divided by 2m = 850 multiplier. That seems like a rather high multiplier. Am I doing these calculations correctly?
Also I note that the formula for light units in the Vray Lights is "lumens per square meter per steradian." The above formula does not include steradians. Is that significant?
So let's say we have a mesh of a light bulb. A light bulb is around 8cm in diameter. So the surface area of a 8cm sphere would be about 200cm or 2m (Area= pi times diameter squared). So 1700 lm divided by 2m = 850 multiplier. That seems like a rather high multiplier. Am I doing these calculations correctly?
Also I note that the formula for light units in the Vray Lights is "lumens per square meter per steradian." The above formula does not include steradians. Is that significant?
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